Stainless Steel Microspheres

300 Series stainless steel is well known for its corrosion resistant properties. Now Scientists are demanding high quality spherical stainless steel microspheres which offer high density (7.8g/cc), high sphericity (>90% round) and corrosion resistance (300 series stainless steel).

A full range of precision sizes are now available from 1-22um on up to 1.0-1.2mm.

Research vial quantities are listed, many sizes have kg quantities in stock for larger project needs.

Deformable Silver Coated PMMA Microsphere Spacers

Silver Coated Glass Microspheres work well for increasing the conductivity of bond lines, but they lack the capability to deform when compressed to give increased conductive contact between the surfaces of the bond line. These newly released Silver Coated PMMA Microspheres offer the low weight deformable pmma cores, and 250nm thick silver coating for high conductivity.

Conductivity of this product has been measured at <0.5ohm per square with a 30% by volume preparation. Sizes available cover both the common 50 micron (45-53um) and 100 micron (90-106um) sizes and many others.

These spheres are perfect for producing anisotropic (only conductive in one direction) conductive bond lines.

Actual bond line thickness achieved will be a function of the assembly pressure and the size spheres selected.

In addition to being high conductive these silver coated PMMA is bio-compatible.

Calculating microspheres per gram

During scientific experiment design and analysis it is common to need to know the number of spheres per gram of dry material. We have put together the table below to help speed up the process.

If you have material of a density different from those listed in the table, divide the number of spheres per gram in the density ~1.0 g/cc column by the true particle density of your material to get an estimate of the number of spheres per gram.

Product Size

Polyethylene
Density ~1.0 (g/cc)

Soda Lime Glass
Density ~2.5 (g/cc)

Lower (um)

Upper (um)

Spheres per Gram

Spheres Per Gram

20

27

147,162,715

58,630,564

27

32

74,393,558

29,638,868

32

45

33,467,185

13,333,540

45

53

16,233,536

6,467,544

53

63

9,788,528

3,899,812

63

75

5,813,720

2,316,223

75

90

3,401,258

1,355,083

90

106

2,029,192

808,443

106

125

1,239,525

493,835

125

150

734,672

292,698

150

180

425,157

169,385

180

212

253,649

101,055

212

250

154,941

61,729

250

300

91,834

36,587

300

355

54,371

21,662

355

425

32,196

12,827

425

500

19,305

7,691

500

600

11,479

4,573

600

710

6,796

2,708

710

850

4,025

1,603

850

1000

2,413

961

1180

1400

890

354

1400

1700

513

204

1700

2000

302

120

2000

2360

184

73

2360

2800

111

44

2800

3350

66

26

Note: This table assumes the mean diameter is half way between the upper and lower size.

Monodisperse Silica Nanospheres and Microspheres – Dry Powder

Scientists are always pushing the limits of the technology and looking for more precise products and equipment to enable the next technology. Advances in nanotechnology is what enables this progress. Nanoparticles are particles that have the dimensions of no less than 1 nanometer and no greater than 1000nanometers (1 micron).Nanospheres are specialized highly spherical nanoparticles. In an effort to provide our customers in the nanotechnology industry with specialty nanomaterials, Cospheric LLC has added a selection of highly precise and spherical monodisperse silica nanospheres to their broad product line and created CosphericNano – a website dedicated exclusively to nanospheres and nanoparticles.

Silica nanoparticles (nanospheres) and silica microspheres are now available in distributions of less than 10% CV in the sizes of 0.25 micron, 0.5 micron, 0.62 micron, 1 micron, 4 micron and 8 micron. Each product is extensively characterized under SEM (scanning electron microscope) to ensure perfect sphericity of each nanosphere and tight particle size specifications.

Microspheres as bond line spacers in epoxies

Today’s electronics are demanding tighter and tighter tolerances, and the assembly of many items require holding precise spacing between parts during assembly. The spherical shape and precise sizes available make microspheres the ideal candidate as a precision spacer in various liquid adhesives and epoxies.

Important considerations:

1) The actual bond line will correspond to the largest spheres, not the average size. Narrow size ranges of a few micron ensure the proper gap is maintained.

If a 30um gap is required use a spacer grade size range of 27-30 micron.

If a 40um gap is required use a spacer grade size range of 37-40 micron.

If a 53um gap is required use a spacer grade size range of 50-53 micron.

3) Functionality gained from using different materials.

Glass offers the best mechanical and chemical stability at a wide range of temperatures.

Spacer Grade Glass Microspheres are presently used in gas plasma displays, automotive mirrors, electronic displays, flip chip technology, filters, sporting goods equipment, calibration standards and transformer manufacturing. Every day engineers are finding new and innovative uses for bond line spacers. One area that has had the most publications is in die attachment in the semi-conductor industry, a particularly interesting area is in using spacers for building multi-die packages. Continue reading “Microspheres as bond line spacers in epoxies” »